Talk Composites - The Forum for Advanced Composites

Epoxy gummy and bit sticky

http://www.talkcomposites.com/Topic30498.aspx

By Davi211 - 9/24/2018 11:00:45 AM

Hello,
I'm a first timer with epoxy and I was really careful on the dosage and how long I would mix the resin, I also never mixed more than 300ml at the time.
Now it has cured for around 15 hours but it still feels gummy and it deformed easily if pressed.
For some reason I thought that 15 hours would already provide a hard surface, am I wrong?
I hope so as otherwise could be something much worst  : (
I try to keep the room temperature around 24 degrees it might have gone down a bit during the night

Any idea what could it be?

Full of hope looking forward to any help BigGrin

Davide
By Davi211 - 9/24/2018 2:07:14 PM

 
Matt (Staff) - 9/24/2018 2:02:15 PM

Ahh, then yes, it would be perfectly normal for the resin to be sticky after 15hrs. Because GlassCast 50 is designed for thick section castings it needs to be very slow curing. Otherwise it would overheat during its cure in a situation we call an 'exotherm'. GlassCast 50 will take around 48hrs to cure at 20'C, you should also account for what the ambient temperature drops to during the evening because the time it takes for the resin to cure will depend on the cumulative time and temperature over the whole day and night period; if the temperature dropped to 10 degrees at night for example then this would barely count towards the cure time.

So, for this project, just keep the place warm and leave it for a good while yet!

You just made my day, so happy. BigGrin 

Thanks a lot.